Organ tone chamber



Nov. 16, 1965 L. W. PAVEA ORGAN TONE GHAMBER Filed July 9, 1964 VIlIIIIIIIIIIIII/ll INVENTOR LEONARD W PA V/A AT TORNEV United States Patent 3,217,580 ORGAN TONE CHAMBER Leonard W. Pavia, 460 Columbia Turnpike, Florham Park, NJ. Filed July 9, 1964, Ser. No. 381,332 5 Claims. (Cl. 84374) This invention relates generally to organ tone chambers and specifically to a rotating baflie in a tone chamber for an electric or electronic organ.

It is an object of the invention to impart the air-noise quality of the pipe organ to electric or electronic organ tones.

It is another object of the invention to impart the pipe organ quality of tremolo and vibrato to the electric or electronic organ tones, with clarity of each tonal quality.

It is a further object of the invention to achieve these objects without imparting any intense throbbing or strong pulsing to the tones, that suggest mechanical, artificial interruption, rather than natural acoustic tremolo or vibrato.

These, and other objects or advantages may be attained by the device shown by way of illustration in the drawing, in which,

FIGURE 1 is a perspective view of a tone chamber with part of the walls exploded away.

FIGURE 2 is a view of the vertical shaft mountings.

The pipe organ, referred to as the king of all musical instruments, has tonal qualities which reflect their origin from the movement of air under pressure through pipes. The air-noise quality of the pipe organ tones is sought after and approached, but never quite achieved in electric or electronic organs. It has been found that the interception of sound originating from a transducer energized by an electronic or electric organ, can be so affected as to embody the air noise quality of the pipe organs tones. A bathe, periodically intercepting a portion of the front wave from a transducer, and also periodically intercepting a portion of the back-wave of the transducer, acting at a certain critical, cyclic frequency range produce tremolo vibrato qualities which cause the electrical or electronic organ tones to more closely approach the air-noise quality of the pipe organ tones.

Referring now to the drawings in detail, the tone chamber is a generally rectangular chamber 11, preferably made of a dense, non-resonant material. Relatively thick panels of wood are suitable for this purpose. The upper portion 12 of the chamber 11 is provided with a horizontal partition or floor 13. A generally circular cone aperture 14 is cut in the partition. The basket of a cone-type transducer 15 is attached to the aperture 14, so that the cone completely fills the aperture 14. The preferred type of transducer 15 is one which has a flat response across the entire range of audible frequencies. A transducer 15 which reproduces the lower and middle frequencies may be used, but it should be supplemented by a high frequency transducer, or tweeter 16. The aperture 14 is bridged by a support 17, attached at both ends to the partition 13. The tweeter 16 may be mounted on the support 17.

The vertical side walls of the chamber '11, above the partition 13, are cut-out, on three sides, to form rectangular ports 18 to disperse the sound. These ports are covered with grille cloth 19. The top 20 is made of the same, dense, non-resonant material, to deflect the sound through the ports 19.

Near the top 20, on the inside of the chamber 11, a generally horizontal bracket 21 is attached to the rear wall 22 of the chamber 11. A generally vertical shaft 23, is rotatably mounted on the support 17 and the bracket 21. This shaft carries a pulley 24. A motor 25 is mounted on the bracket 21, and a belt 26 connects the motor shaft to the pulley.

3,217,580 Patented Nov. 16, 1965 Mounted on the shaft 23 below the pulley 24, there is a horizontal support or baffle 27. The horizontal baffle 27 is in the shape of a wedge or a sector of a circle, having an apex angle of approximately 45.

The peripheral edge 28 defines the top of a depending, horizontally-arcuate vertical baffle 29 su'btending the approximately 45 arc of the top bafile 27. This vertical bafile 29 extends downwardly, close to the horizontal partion 13. Increases substantially beyond this 45 size have been found to produce an undesireable, un-natural pulsing giving a perceived sound effect suggestive of opening and closing a door.

At the back of the partition 13, a rectangular port 30 extends from side to side. This permits a portion of the back-wave of the transducer 15 to enter the top of the chamber 11. This back-wave will be intercepted periodically as the horizontal and vertical bafiles 27, 29 rotate, and so will be modulated, first in the quantity of sound projected through the ports 19, and second in the generalized cancelling effect the back wave will have on the front wave from the transducer 15.

The baffles 27, 29 are counterbalanced by the arm 31 extending on the opposite side of the shaft 23, and by the counterweight 32 on the end thereof.

Different degrees of speed of rotation of the baffles 27, 29 produce different auditory impressions. The following are examples.

Chorus, in a pipe organ, may be generally defined as a tonal quality derived from blending or mixing individual tone sources. Changes in atmospheric pressure and wind pressure give a random character to the tone due to changes in pitch in the various ranks of pipes, producing a pleasing ensemble blend. Electronic organs may not have this quality highly developed. Operation of the baffles 27, 29 at the rate of approximately one cycle per second will supply a realistic chorus effect, closely simultating a pipe organ.

A more subtle blending is required for the celeste quality of tone. Celeste in a pipe organ is achieved by two ranks of pipes of generally equal pitch and equal tonality, but one tuned slightly sharp or flat with respect to the other. With the bafiles rotated at the general range of two to four cycles per second, the limited pulsing is less defin able, and imparts a sense movement enjoyed with certain organ stops.

A tremolo-vibrato which is pleasant for all four families of organ stops, can be attained by rotation at the rate of approximately five to eight cycles per second. There is no violent pulsing, but a mild, subtle, modification of tone which never reduces more than slightly the volume. It is believed that the lower frequency tones are modified in amplitude, and the higher tones are frequency modulated.

The foregoing device is illustrative of an embodiment of the invention. Changes may be made in the construction, selection, and arrangement of the parts within the scope of the claims without departing from the spirit of the invention.

What is claimed:

1. An organ tone chamber comprising,

(a) a chamber,

(b) a partition in the chamber having an aperture for a transducer,

(c) a transducer in the aperture,

(d) a generally horizontal sector mounted for rotation over the aperture,

(e) a generally vertical arcuate bafile depending from the horizontal sector,

(f) a means to rotate the sector and depending portion,

(g) the radius of rotation of the sector being substantially the radius of the aperture,

(h) the bottom edge of the vertical baffie being in sub- 1 w stantial registration with the aperture for the transducer, during rotation, and

(i) the means to rotate the sector and portion to intermittently intercept sound from the transducer.

2. An organ tone chamber comprising,

(a) the device according to claim 1 and (b) the sector having an apex angle of approxi mately 45.

3. An organ tone chamber comprising,

(a) the device according to claim 1 and (b) the baflle rotating at the rate of approximately one to eight cycles per second.

4. An organ tone chamber comprising,

(a) the device according to claim 1 and (b) a back-wave port in the partition, outside of the area within the circle of rotation of the baflle.

5. An organ tone chamber comprising,

(a) a generally rectangular chamber,

(b) a generally horizontal partition dividing the chamber into upper and lower compartments,

(c) ports for the emission of sound on three sides of the upper compartment,

(d) an aperture for a transducer in the partition,

(e) a generally vertical, rotatable shaft mounted in the upper compartment,

(f) a generally horizontal arm mounted on the rotatable shaft.

(g) a sector on the arm having an apex of approximately 45 at the center of rotation,

(h) a generally vertical, arcuate baffle depending from the periphery of the sector, and having its bottom edge in substantial registration with the aperture, with its radius of rotation substantially the radius of the aperture,

(i) means to rotate the shaft at approximately one to I eight cycles per second, and

(j) a back-wave port in the partition, outside the radius of rotation.

No references cited.

20 LEO SMILOW, Primary Examiner. 

1. AN ORGAN TONE CHAMBER COMPRISING, (A) A CHAMBER, (B) A PARTITION IN THE CHAMBER HAVING AN APERTURE FOR A TRANSDUCER, (C) A TRANSDUCER IN THE APERTURE, (D) A GENERALLY HORIZONTAL SECTOR MOUNTED FOR ROTATION OVER THE APERTURE, (E) A GENERALLY VERTICAL ARCUATE BAFFLE DEPENDING FROM THE HORIZONTAL SECTOR, (F) A MEANS TO ROTATE THE SECTOR AND DEPENDING PORTION, (G) THE RADIUS OF ROTATION OF THE SECTOR BEING SUBSTANTIALLY THE RADIUS OF THE APERTURE, (H) THE BOTTOM EDGE OF THE VERTICAL BAFFLE BEING IN SUBSTANTIAL REGISTRATION WITH THE APERTURE FOR THE TRANSDUCER, DURING ROTATION, AND (I) THE MEANS TO ROTATE THE SECTOR AND PORTION TO INTERMITTENTLY INTERCEPT SOUND FROM THE TRANSDUCER. 